2022-11-24 17:24:21

by John Keeping

Subject: [PATCH] usb: gadget: f_fs: use io_data->status consistently

Commit fb1f16d74e26 ("usb: gadget: f_fs: change ep->status safe in
ffs_epfile_io()") added a new ffs_io_data::status field to fix lifetime
issues in synchronous requests.

While there are no similar lifetime issues for asynchronous requests
(the separate ep member in ffs_io_data avoids them) using the status
field means the USB request can be freed earlier and that there is more
consistency between the synchronous and asynchronous I/O paths.

Cc: Linyu Yuan <[email protected]>
Signed-off-by: John Keeping <[email protected]>
---
drivers/usb/gadget/function/f_fs.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 73dc10a77cde..1221f0d1b1a9 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -825,8 +825,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
{
struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
work);
- int ret = io_data->req->status ? io_data->req->status :
- io_data->req->actual;
+ int ret = io_data->status;
bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;

if (io_data->read && ret > 0) {
@@ -840,8 +839,6 @@ static void ffs_user_copy_worker(struct work_struct *work)
if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
eventfd_signal(io_data->ffs->ffs_eventfd, 1);

- usb_ep_free_request(io_data->ep, io_data->req);
-
if (io_data->read)
kfree(io_data->to_free);
ffs_free_buffer(io_data);
@@ -856,6 +853,9 @@ static void ffs_epfile_async_io_complete(struct usb_ep *_ep,

ENTER();

+ io_data->status = req->status ? req->status : req->actual;
+ usb_ep_free_request(_ep, req);
+
INIT_WORK(&io_data->work, ffs_user_copy_worker);
queue_work(ffs->io_completion_wq, &io_data->work);
}
--
2.38.1

2022-11-25 03:37:43

by Linyu Yuan

Subject: Re: [PATCH] usb: gadget: f_fs: use io_data->status consistently

Reviewed-by: Linyu Yuan <[email protected]>


On 11/25/2022 1:04 AM, John Keeping wrote:
> Commit fb1f16d74e26 ("usb: gadget: f_fs: change ep->status safe in
> ffs_epfile_io()") added a new ffs_io_data::status field to fix lifetime
> issues in synchronous requests.
>
> While there are no similar lifetime issues for asynchronous requests
> (the separate ep member in ffs_io_data avoids them) using the status
> field means the USB request can be freed earlier and that there is more
> consistency between the synchronous and asynchronous I/O paths.
>
> Cc: Linyu Yuan <[email protected]>
> Signed-off-by: John Keeping <[email protected]>
> ---
> drivers/usb/gadget/function/f_fs.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 73dc10a77cde..1221f0d1b1a9 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -825,8 +825,7 @@ static void ffs_user_copy_worker(struct work_struct *work)
> {
> struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
> work);
> - int ret = io_data->req->status ? io_data->req->status :
> - io_data->req->actual;
> + int ret = io_data->status;
> bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
>
> if (io_data->read && ret > 0) {
> @@ -840,8 +839,6 @@ static void ffs_user_copy_worker(struct work_struct *work)
> if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
> eventfd_signal(io_data->ffs->ffs_eventfd, 1);
>
> - usb_ep_free_request(io_data->ep, io_data->req);
> -
> if (io_data->read)
> kfree(io_data->to_free);
> ffs_free_buffer(io_data);
> @@ -856,6 +853,9 @@ static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
>
> ENTER();
>
> + io_data->status = req->status ? req->status : req->actual;
> + usb_ep_free_request(_ep, req);
> +
> INIT_WORK(&io_data->work, ffs_user_copy_worker);
> queue_work(ffs->io_completion_wq, &io_data->work);
> }